Ring-mold.



H W. ALEXANDER.

RING MOLD. APPHCATION FILED FEB. 13, 1911.

Patented Oct. 1, 1918.

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H WALTER ALEXANDER, 0F SAC CITY, IOWA, ASSIG-NOR TO B. B. GREENBLATT, OF OMAHA, NEBRASKA.

RING-MOLD.

Specification of LettersPatent.

Patented Oct. 1, 1918.

Application filed February 13,1917. Serial No. 148,441.

To all whom it may concern:

Be it known that 1', H WALTER ALEXAN- DER, a citizen of the United States, and a resident of Sac City, in the county of Sac and State of Iowa, have invented certain new and useful Improvements in Ring- Molds, of which the following is a speci cation. j Myinvention relates .to molds for casting metal, and particularly to molds for casting finger-rings and the like from precious metals such as gold. The general object. of my invention is to provide a permanent mold for casting finger-rings, the mold being adapted for producing a ring having a crown Or bezel for receiving a jewel, and the. body of the ring being shapedto facilitate rolling or swaging operations thereon for varying the size thereof after it is cast. A further objectof my invention is to provide, .for molds of this class, a head or crown-core having internal vents. for the prong-channels, whereby there may be attained a perfect flow of the molten metal into said prong-channels. Further objects of my invention are to provide special venting means for the main mold-cavity, to provide simple and convenient means for supporting the mold-parts in assembled relation, and to provide a mold of the class described in which the main body-portion is of hard argillaceous material and of a form substantially concentric with the mold-cavity, and thereby to avoid cracking or checking of the moldby unequal expansionthereof' when the same is heated.

In the accompanying drawings Figure 1 is an axial'section of a mold embodying my invention, Fig. 2 is a front view thereof with the center-core andthe front half of the mold removed, Fig 3 isa section in the horizontal plane of the line 33 of Fig. 2, Fig. at is a detail side view of the crowncore, and Fig. 5 is a vertical section on the plane of the line 55 of Fig. 4:.

The main body of the mold provided by my invention is preferably of hard argillaceous material, being a composition of clay, hardened by drying and by firing in a suitable kiln. The general form of the mold is preferably cylindrical, being substantially concentric with the annular mold-cavity, so that there is approximately a uniform thickness of material around the outer sides of the mold-cavity. Extending axially of the molds-body there is a tapering or truncoconical opening adapted to receive a metallic expanding and contracting core, such as that shown in U. S. Letters Patent No. 1,183,515, issued tome May 16, 1916. The axially-perforate cylindrical mold-body is preferably parted in the plane of the moldcavity to form front and rear annular moldportions 6 and 7, the mold-cavity being formed by recesses .8 and 9 in the adjacent faces of the parts, adjoining the bore thereof. When the frontand rear mold-parts 6 and 7 are assembled they are held in coaxial relation by the core 10, of which the structure and mode of operation are fully set forth in the LettersPatent above mentioned. The mold-parts 6 and 7 are surrounded peripherally by metal clamp-bands .11 and 12, the ends. of said bands being turned outwardly and being drawn toward each other by a clamp-screw 13, asshown in Fig. 2. The clamp-band 12 has at opposite sides thereof hooked projecting sidepieces 1i adapted to engage slidably the parallel side-portions of a. supporting frame formed by a U-shaped rod or heavy wire 15, said supporting frame beingheld in a vertical position by any suitable means. The mold-parts are held together axially by means of two or more resilient split-rings 16, which extend around the mold so that their ends bear against the front and rear faces thereof, as. indicated in Fig. 1.

At the upper side of the mold there is a gate or pouring-channel formed by recesses 17 in theadjoining faces of the parts. 6 and 7, said channel being approximately conical and tapering from the upper to the lower end, where. it joins the-mold-cavity formed by the. recesses. 8 and 9. A main vent, for the escape of air and gas from the mold-cavity, is formed by radial channels 18 in the adjoiningfaces of the mold-parts, the same preferably being disposed at the upper part of the mold near one side of the pouringchannel, as shown in Fig. 2. A further venting means is provided, consisting of shallow channels a formed in the adjoining faces of the parts 6. and 7, said channels a not communicating directly with the mold cavity but extending concentrically therewith and having radial portions 7) extending to the peripheral edges of the mold. The channels a and 6 form passages for the escape of air and gas from the pores or interstices of the material forming the mold, and also permit the free escape of any gases that may pass out from the mold-cavity at the parting-plane between the contacting faces 0 around the mold-cavity. It willbe understood that while said faces 0 fit together so closely as to prevent escape of molten metal from the mold-cavity, or the formation of a fin on the casting, the contact between said surfaces is, in practice, not necessarily such as to form a gas-tight joint, and the escape of gases through said joint is facilitated by reducing to a minimum the radial distance traversed thereby before reaching a clear or unobstructed space, such as that afforded by the channel a.

When the mold is to be used for casting rings having a bezel or crown, for receiving a jewel or setting, there is provided in the parts 6 and 7 a trunco-conical recess of which the axis extends vertically in the parting plane of the mold, and of which the smaller end connects with the mold-cavity, while the larger end extends to, the lower side of the mold. In said. recess there is disposed a metal crown-core of which the form is shown in detail in Figs. 4 and 5. Said crown-core has a trunco-conical upper endportion 19 which extends through the moldcavity into contact with the center-core 10, and the main body 20 of the crown-core has in its upper portion a plurality of prongchannels 21 of which the inner sides lie in a cone-surface formed by downward prolongation of the upper end-portion 19. From the inner side of each of the prong-channels a vent-slit 22 extends in radially of the coreaxis and communicates with a central conical cavity or recess 23 in the core-body, said cavity or recess beingopen at the bottom. Pins 24, integral with the core-body,- extend downwardly therefrom and rest upon a metal shelf 25 of which the end-portions are secured to the support 15. The prong-channels of the crown-core are usually six in number, and to insure the positioning of the core in the mold so that the crown-prongs will be symmetrical to the plane of the ring, there is provided a pin 26 passing transversely through the core near the lower end thereof, the ends of said pin fitting into recesses therefor in the mold-parts at the parting-plane, as shown in Fig. 2. The ventslits 22 extend substantially the full length of the prong-channels, and said slits are made so narrow that the molten metal flowing into the prong-channels will not flow through the slits into the central cavity 23 of the core. In making the core, the vent slits may be. conveniently formed by the use of a very thin circular saw of a diameter such as indicated by the curvature of the upper and lower ends of the slits indicated in Fig. 5.

In the use of the mold, when the molten way be trapped therein, so that perfectlycast-aron 's ma be obtained for the bezel 1 or crown of the ring. In molds of this class heretofore produced, it has been customary to vent the prong-channels at the lower ends thereof, but with such venting the castings produced are often rendered defective by having blow-holes in the sides of the prongs, particularly on the inner sides thereof near the point of their juncture with the main body of the ring. Such blow-holes are entirely avoided by the use of the centrallyvented crown-core.

It may be noted that, in the mold shown, the 1n0ld-cavity is so formed that the ring produced therein will have an extra thickness of material at the side adjoining the crown, and also at the side diametrically opposite the crown. The latter material is provided to enable the enlargement of the ring by rolling or swaging thereof after it is cast, without reducing the normal thickness of metal therein, which is that provided at the points intermediate the thickened portlons. j

From the foregoing it will be seen that my invention provides a convenient and efiicient finger-ring mold for goldsmiths and jewelers use, in which all the parts are sub stantially permanent and capable of repeated use without appreciable deterioration. It will also be seen that by the special venting means employed therein, it is possible to produce invariably a perfectly-cast ring, requiring only the removal of the sprue and the usual polishing to complete the same ready for receiving a jewel or setting.

Now, having described my invention, what I claim and desire to secure by Letters Patent is:

1. In a finger-ring mold, a crown-core comprising a hollow conical metal body having prong-channels in the outer portion thereof and vent-slits extending from the inner sides of said prong-channels to the central cavity of the body.

2. In a finger-ring mold, a crown-core comprising a trunco-conical body of metal, having an open central cavity, there being longitudinally extending prong-channels on the outer side of the body, and continuous vents extending longitudinally of said prong-channels and communicating wit-h the central cavity.

3. In a ring-mold, the combination with mold-parts having an annular mold-cavity and a trunco-conical core-recess communieating with one side of the mold-cavity,=of a crowncore fitting in said recess and forming the inner wall of channels for crownprongs, said core having a central opening and vents connecting said central opening With the adjacent sides of the prong-chan nels substantially throughout their length.

4. A permanent mold for finger-rings, comprising annular mold-parts having a parting-plane perpendicular to the axis thereof, a center-core extending through the central openings of said mold-parts to aline them axially, the mold-parts being recessed at the parting-plane to form an annular mold-cavity around the center-core and to form a pouring-gate and a crown-core recess, and a metal crown-core seated in said recess and having internally-vented prongchannels formed therein. 7

5. In a mold for finger-rings, a substantially conical crown-core of metal, having a central opening and radial vent-slits eXtending from said opening to substantially all the longitudinal portions of prong-channels formed in the outer portion of the corebody.

H WALTER ALEXANDER.

00,1 of this patent my be obtained for in cent: each, by draining the commissioner o1 Patentl.

Washington, D. 0." 

